path: root/node/config.go

// Copyright 2015 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.

package node

import (
    "crypto/ecdsa"
    "encoding/json"
    "fmt"
    "io/ioutil"
    "net"
    "os"
    "path/filepath"
    "runtime"
    "strings"

    "github.com/ethereum/go-ethereum/common"
    "github.com/ethereum/go-ethereum/crypto"
    "github.com/ethereum/go-ethereum/logger"
    "github.com/ethereum/go-ethereum/logger/glog"
    "github.com/ethereum/go-ethereum/p2p/discover"
    "github.com/ethereum/go-ethereum/p2p/nat"
)

var (
    datadirPrivateKey   = "nodekey"            // Path within the datadir to the node's private key
    datadirStaticNodes  = "static-nodes.json"  // Path within the datadir to the static node list
    datadirTrustedNodes = "trusted-nodes.json" // Path within the datadir to the trusted node list
    datadirNodeDatabase = "nodes"              // Path within the datadir to store the node infos
)

// Config represents a small collection of configuration values to fine tune the
// P2P network layer of a protocol stack. These values can be further extended by
// all registered services.
type Config struct {
    // DataDir is the file system folder the node should use for any data storage
    // requirements. The configured data directory will not be directly shared with
    // registered services, instead those can use utility methods to create/access
    // databases or flat files. This enables ephemeral nodes which can fully reside
    // in memory.
    DataDir string

    // IpcPath is the requested location to place the IPC endpoint. If the path is
    // a simple file name, it is placed inside the data directory (or on the root
    // pipe path on Windows), whereas if it's a resolvable path name (absolute or
    // relative), then that specific path is enforced. An empty path disables IPC.
    IpcPath string

    // This field should be a valid secp256k1 private key that will be used for both
    // remote peer identification as well as network traffic encryption. If no key
    // is configured, the preset one is loaded from the data dir, generating it if
    // needed.
    PrivateKey *ecdsa.PrivateKey

    // Name sets the node name of this server. Use common.MakeName to create a name
    // that follows existing conventions.
    Name string

    // NoDiscovery specifies whether the peer discovery mechanism should be started
    // or not. Disabling is usually useful for protocol debugging (manual topology).
    NoDiscovery bool

    // Bootstrap nodes used to establish connectivity with the rest of the network.
    BootstrapNodes []*discover.Node

    // Network interface address on which the node should listen for inbound peers.
    ListenAddr string

    // If set to a non-nil value, the given NAT port mapper is used to make the
    // listening port available to the Internet.
    NAT nat.Interface

    // If Dialer is set to a non-nil value, the given Dialer is used to dial outbound
    // peer connections.
    Dialer *net.Dialer

    // If NoDial is true, the node will not dial any peers.
    NoDial bool

    // MaxPeers is the maximum number of peers that can be connected. If this is
    // set to zero, then only the configured static and trusted peers can connect.
    MaxPeers int

    // MaxPendingPeers is the maximum number of peers that can be pending in the
    // handshake phase, counted separately for inbound and outbound connections.
    // Zero defaults to preset values.
    MaxPendingPeers int

    // HttpHost is the host interface on which to start the HTTP RPC server. If this
    // field is empty, no HTTP API endpoint will be started.
    HttpHost string

    // HttpPort is the TCP port number on which to start the HTTP RPC server. The
    // default zero value is/ valid and will pick a port number randomly (useful
    // for ephemeral nodes).
    HttpPort int

    // HttpCors is the Cross-Origin Resource Sharing header to send to requesting
    // clients. Please be aware that CORS is a browser enforced security, it's fully
    // useless for custom HTTP clients.
    HttpCors string

    // HttpModules is a list of API modules to expose via the HTTP RPC interface.
    // If the module list is empty, all RPC API endpoints designated public will be
    // exposed.
    HttpModules []string
}

// IpcEndpoint resolves an IPC endpoint based on a configured value, taking into
// account the set data folders as well as the designated platform we're currently
// running on.
func (c *Config) IpcEndpoint() string {
    // Short circuit if IPC has not been enabled
    if c.IpcPath == "" {
        return ""
    }
    // On windows we can only use plain top-level pipes
    if runtime.GOOS == "windows" {
        if strings.HasPrefix(c.IpcPath, `\\.\pipe\`) {
            return c.IpcPath
        }
        return `\\.\pipe\` + c.IpcPath
    }
    // Resolve names into the data directory full paths otherwise
    if filepath.Base(c.IpcPath) == c.IpcPath {
        if c.DataDir == "" {
            return filepath.Join(os.TempDir(), c.IpcPath)
        }
        return filepath.Join(c.DataDir, c.IpcPath)
    }
    return c.IpcPath
}

// DefaultIpcEndpoint returns the IPC path used by default.
func DefaultIpcEndpoint() string {
    config := &Config{DataDir: common.DefaultDataDir(), IpcPath: common.DefaultIpcSocket}
    return config.IpcEndpoint()
}

// HttpEndpoint resolves an HTTP endpoint based on the configured host interface
// and port parameters.
func (c *Config) HttpEndpoint() string {
    if c.HttpHost == "" {
        return ""
    }
    return fmt.Sprintf("%s:%d", c.HttpHost, c.HttpPort)
}

// DefaultHttpEndpoint returns the HTTP endpoint used by default.
func DefaultHttpEndpoint() string {
    config := &Config{HttpHost: common.DefaultHttpHost, HttpPort: common.DefaultHttpPort}
    return config.HttpEndpoint()
}

// NodeKey retrieves the currently configured private key of the node, checking
// first any manually set key, falling back to the one found in the configured
// data folder. If no key can be found, a new one is generated.
func (c *Config) NodeKey() *ecdsa.PrivateKey {
    // Use any specifically configured key
    if c.PrivateKey != nil {
        return c.PrivateKey
    }
    // Generate ephemeral key if no datadir is being used
    if c.DataDir == "" {
        key, err := crypto.GenerateKey()
        if err != nil {
            glog.Fatalf("Failed to generate ephemeral node key: %v", err)
        }
        return key
    }
    // Fall back to persistent key from the data directory
    keyfile := filepath.Join(c.DataDir, datadirPrivateKey)
    if key, err := crypto.LoadECDSA(keyfile); err == nil {
        return key
    }
    // No persistent key found, generate and store a new one
    key, err := crypto.GenerateKey()
    if err != nil {
        glog.Fatalf("Failed to generate node key: %v", err)
    }
    if err := crypto.SaveECDSA(keyfile, key); err != nil {
        glog.V(logger.Error).Infof("Failed to persist node key: %v", err)
    }
    return key
}

// StaticNodes returns a list of node enode URLs configured as static nodes.
func (c *Config) StaticNodes() []*discover.Node {
    return c.parsePersistentNodes(datadirStaticNodes)
}

// TrusterNodes returns a list of node enode URLs configured as trusted nodes.
func (c *Config) TrusterNodes() []*discover.Node {
    return c.parsePersistentNodes(datadirTrustedNodes)
}

// parsePersistentNodes parses a list of discovery node URLs loaded from a .json
// file from within the data directory.
func (c *Config) parsePersistentNodes(file string) []*discover.Node {
    // Short circuit if no node config is present
    if c.DataDir == "" {
        return nil
    }
    path := filepath.Join(c.DataDir, file)
    if _, err := os.Stat(path); err != nil {
        return nil
    }
    // Load the nodes from the config file
    blob, err := ioutil.ReadFile(path)
    if err != nil {
        glog.V(logger.Error).Infof("Failed to access nodes: %v", err)
        return nil
    }
    nodelist := []string{}
    if err := json.Unmarshal(blob, &nodelist); err != nil {
        glog.V(logger.Error).Infof("Failed to load nodes: %v", err)
        return nil
    }
    // Interpret the list as a discovery node array
    var nodes []*discover.Node
    for _, url := range nodelist {
        if url == "" {
            continue
        }
        node, err := discover.ParseNode(url)
        if err != nil {
            glog.V(logger.Error).Infof("Node URL %s: %v\n", url, err)
            continue
        }
        nodes = append(nodes, node)
    }
    return nodes
}